Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0042961 (volvulus)
 4,305 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Nematode infections of the eye are common in different parts of the world, but some are usually encountered only in developing nations, such as onchocerciasis and cysticercosis. Ocular toxocariasis is a well-known cause of unilateral ocular disease affecting mainly children and young adults, and is usually caused by T canis. Prevention of ocular toxocariasis is based on such measures as appropriate health care for dogs and cats, including regular anthelmintic treatments, preventing contamination of the environment with feces, and promoting responsible pet ownership [1,49-51]. Onchocerciasis is caused by infection with the filarial parasite O volvulus, and occurs in endemic areas along rivers and streams. In hyperendemic areas almost every person is infected and about half of the population is eventually blinded by onchocerciasis. Because of this, elimination of host-vector contact is very important. DUSN is caused by a motile nematode and is found in the Southeastern and Midwestern United States and in many parts of the world. In Brazil, DUSN is becoming an important cause of posterior uveitis in children and young healthy adults. The destruction of the worm during the early stages of the disease can prevent progression of the visual loss. It is important to remain aware of this entity, not only in areas where it has been described, but also in regions not yet identified as being endemic [52]. Cysticercosis is caused by the encystment of the larvae of the tapeworm T solium, and usually results from ingesting eggs from food, water, or other material contaminated with human feces. Surgical removal of the cyst is usually indicated when possible.
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PMID:Nematode infections of the eye: toxocariasis, onchocerciasis, diffuse unilateral subacute neuroretinitis, and cysticercosis. 1243 84

Onchocerciasis is caused by the parasitic worm Onchocerca volvulus, which releases millions of offspring (microfilariae). Microfilariae migrate through the skin and can enter the anterior or posterior regions of the eye. While alive, the microfilariae appear to cause little or no inflammation, being in the anterior chamber. However, when they die, either by natural attrition or after chemotherapy, the host response to degenerating worms can result in ocular inflammation (keratitis, uveitis, chorioretinitis, neuritis of the optic nerve) that causes progressive loss of vision and ultimately leads to blindness. With the use of a mouse model of corneal inflammation to study the pathogenesis of ocular onchocerciasis by injecting worm extracts directly into the corneal stroma, it was found that worms treated with the antibiotic doxycycline, which destroys Wolbachia, induced lower corneal stromal thickness and stromal haze (indicators of corneal oedema and opacity) and neutrophil infiltration compared with both untreated worms and worms that do not harbour Wolbachia. These data indicate that endosymbiotic Wolbachia bacteria in filarial parasites have a key role in the pathogenesis of river blindness. Worms recovered from patients treated for 6 weeks with doxycycline contained fewer Wolbachia bacteria and had abnormal embryogenesis, indicating a role for Wolbachia in the survival or fecundity of the worms. Antibiotic treatment may also reduce the severity of the inflammatory response in the cornea.
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PMID:[Ocular onchocerciasis: a key role for Wolbachia]. 1797 45

Several factors acting in concert now place US residents, returning travelers, and expatriates at risks of contracting ocular filariasis including increasing seroprevalence rates of zoonotic filariasis, international travel bringing tourists to and expatriates from filariasis-endemic regions, and warming temperatures extending distribution ranges of arthropod vectors. To describe the epidemiology and outcomes of ocular filariasis and to recommend strategies for the diagnosis, management, and prevention of ocular filariasis, internet search engines were queried with the key words in order to examine case reports and series of ocular filariasis in the US and elsewhere. Descriptive epidemiological, morphological, and molecular evidence now support increasing cases of ocular filariasis in domestic and wild animals and humans, with most cases caused by filarial worms including Dirofilaria repens and other zoonotic Dirofilaria species and Onchocerca lupi and other zoonotic Onchocerca species. Clinicians should maintain early suspicion of ocular filariasis in US residents, returning travelers, and expatriates who complain of combinations of red eye, eye pain, foreign body sensation, reduced visual acuity, and migrating ocular worms, even without significant peripheral eosinophilia or microfilaremia. Microfilariae of Wuchereria bancrofti, Brugia malayi, and O. volvulus may traverse the eye, but can usually be treated medically. Mobile adult worms trapped in the subconjunctiva or anterior chamber should be removed by ophthalmologists to permit species identification, prevent posterior uveitis and iritis, and stop worm migration into the posterior chamber which could require lens removal and vitrectomy for worm extraction causing further eye damage.
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PMID:Ocular Filariasis in US Residents, Returning Travelers, and Expatriates. 2715 10